Xerographic apparatus



June 2, 1 A. J. CERASANI ETAL 3,13

XEROGRAPHIC APPARATUS 6 Sheets-Sheet 1 Original Filed April 2 1959 K INVENTOR AMERICO J. CERASANI JOSEPH J. CQDICHINI BY MILES DAVIS WILLIAM G. LEWIS A TTORNEV June 2, 1964 A. J. CERASANI ETAL 3,135,130

XEROGRAPHIC APPARATUS Original Filed April 2. 1959 6 Sheets-Sheet 2 INVENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS 7WILLIAM G. LEWIS ATTORNEY June 2, 1964 A. J. CERASANI ETAL 3,135,180

XEROGRAPHIC APPARATUS Original Filed April 2. 1959 6 Sheets-Sheet I5 75 DEVELOPING EXPOSING o INVENTOR AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS yWILLIAM G LEWIS A T TORNE Y June 2, 1964 A. J. CERASANI ETAL 3,135,180

XEROGRAPHIC APPARATUS 6 Sheets-Sheet 4 Original Filed April 2, 1959 ll v. w M H 8 M C m um m n WCwB A .ma/ @H M PS I EEL w q AJMW BY y,

June 1964 A. J. CERASANI ETAL 3,

XEROGRAPHIC APPARATUS 6 Sheets-Sheet 5 Original Filed April 2, 1959 INENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS QMLLIAM G. LEWIS M AM /Qa TTORIVEY June 2, 1 4 A. J. CERASANI ETAL 3,135,180

' XEROGRAPHIC APPARATUS Original Filed April 2 1959 6 Sheets-Sheet e ||5V SON INVENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS WILLIAM G. LEWIS ywq M ATTORNEY United States Patent F 4 Claims. (Cl. 951.7)

This invention relates to improvements in xerographic reproduction apparatus and particularly to improved apparatus for placing a control pattern on the photoconductive surface of a xerographic reproducing machine. More specifically, this invention relates. to improvements in xerographic reproduction apparatus by which an electrostatically charged portion of the photoconductive surface is discharged in response to an electrical signal received from another operation of the, machine, for exam.- ple, the insertion of original copy to be reproduced. The dischargingof the electrostatic charge results in a control pattern which may be used to provide controls for other operations or equipment. This is a divisional application of our copending application S.N. 803,800, filed April 2, 1959. t

In the process of xerography, for example, as disclosed in Carlson Patent 2,297,691, issued Ocober 6, 1942,.a xerographic plate comprising a layer of photoconductive insulating material on a conductive backing is given a uniform electric charge over its surface and is then exposed to the subject matter to be reproduced, usually ,by conventional projection techniques, This exposure discharges the plate areas in accordance with the radiation intensity that reaches them, and thereby creates an electrostatic latent imageon or in the photoconductive layer. Development of the latent image is efiected with an electrostatically charged, finely divided material such as anelectroscopic powder that is brought into surface contact with the photoconductive layer and is held thereon velectrostatically in a pattern corresponding'to the elec' .trostatic latent image. Thereafter, the developed xerographic powder image is usually transferred to a support surface to which it may be fixed by any suitable means.

It is the practice on automatic xerographic printers of types such as disclosed in copending application S.N. 796,561, entitled Xerographic Reproducing Apparatus, filed March 2, I959, in'the name of- Stem R. Johanson, now Patent No. 3,049,968 to operate a continuously moving paper web support surface from a supply roll to takeup roll inbetween which xerographic reproductions are printed thereon. Since the: originalfrom which the reproduction is formed, may vary in dimension, can be reproduced by the Xerographio apparatus'in magnified relation, or can be fed to the xerographic apparatus'in untimed relation, a wide variance of spacing between'successive prints mayresult. Blank paper occurring on the web between xerographicprints, exclusive of border width for the prints, is scrap for disposal. Sinceit isthe usual practice tomove the paper web at a constant rate of approximately 20 feet per minute ('4 inches per second), a'continued absence of reproductioncauses a sizable accumulation of scrap paper on the takeup roll; as, for example, one minutes hesitation on the part of a' human operator between feeding successive'originals to. the apparatus effects: approximately 20 feet of scra'ppaper. On

the other hand, accurately timed successive feeding of originals for ll /z-inch reproductions results'in approximately 20 xerographically printed reproductions in the same web lengthQ p Heretofore, the usual practicehas" been to periodically remove the 'takeup roll with the paper'web wound thereon 3,135,180 Patented June 2, 1964 to another locationwhereat the paper was unwound and with a manually operative cutter, cut the web so as to effect an approximate border on the leading and trailing edge of each xerographic print. Scrap resulting therefrom was then disposed of. By these former cutting means, considerable delay was incurred in elfecting availability of the xerographic reproduction and furthermore required the services of additional personnel employed for this specific function.

Because of the variable occurrence of the cut on the moving web, a cutter mechanism to be effective mustbe responsive to a reference means on the web. In order for the cutter to respond in spaced relation to the reproduction the reference means must emanate, from relation of the original to be reproduced whereby this relation is carried forthv to the reproduction on the support surface. When, as here, it is intended to cut the web in relation to both the leading and trailing edge of a reproduction, the reference means must be associated with its respective edge and be distinguishable in order that the cutter be made to respond accordingly, that is, to cut the web in advance of a leading edge and after a trailing edge.

Because of the unwieldly length of scrap that might otherwise accumulate, it is also desirable to simulate reference means on scrap paper at regulated intervals in the absence of xerographic reproductions to which the cutter responds to cut the scrap into prescribed lengths. Since, in the direction of movement, the portion of web following the trailing edge of a reproduction constitutes scrap, whereas the portion of web following the leading edge of a reproduction constitutes a xerographic print, association of reference with the respective cut permits operation of apparatus to separate scrap and reproductions. Therefore, the simulated reference means on scrap paper is distinguishable by the cutter mechanism similarly as a trailing edge. Also, the situation occasionally a'situation, a minimum or insufiicient border width'is available for both reproductions such that only one cut is possible and vbecause both are reproductions the reference means is to be distinguished by the cutter mechanism as a leading edge to effect proper separation and disposition of both.

It is important, therefore, in the combination of situations mentioned above, that a cutter be responsive to a reference means, that the. means be effective to distinguish; between leading and trailing edges and between xerographic reproduction and scrap and have means of taking into account the close spacing of successive reproductions. The principal object of this invention is to improve xerographic reproduction apparatus for placing a control pattern on the photoconductive surface.

A further object of this invention is to improve the means for discharging a uniform electrostatic charge on the photoconductive surface of' a xerographic reproducing machine, in response to asignal received from another operation of the machine or from an exterior source. It is a further object of this invention to form electrostatic latent imagecontrol patterns on a xerographic. plate in spaced relation to electrostatic latent images of copy to. be reproduced. r

These and other objects of the invention are attained by means of a plurality of lights placed in close relationship to the photoconductive surface. Two of said pattern area and the remaining lights'being responsive to an electrical circuit whereby they are intermittently illuminated to discharge the electrostatic charge on the photoconductive surface in response to a predetermined signal. a a

For a better understanding of the invention as well as j'o'ther objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein: FIG. 1 is a schematic side elevation of an automatic xerographic printer employing the apparatus of the invention; -FIG. 2 is an isometric view of the detection apparatus of the invention over which the transport means of the xerographic unit moves an original to be reproduced; FIG. 3 is an isometric view of the exposure slit and marking apparatus ofthe invention for forming electrostatic latent image control patterns on a xerographic drum;

FIG. 4 is a developed surface of a'xerographic drum "through the cycle of charging, exposing, developing, transferring and cleaning; FIG. 5 is a sectional view taken substantially on the line 55 of FIG. 4 illustrating the marker apparatus of the invention in relation to a xerographic drum;

FIG.'6 is an isometric view of the drive assembly and the reference scan apparatus taken from the opposite side of FIG. 1;

FIG. 7 is a sectional isometric view taken through the scan apparatus illustrated in FIG. 6; FIG. 8 is an exploded isometric view taken from the opposite side of FIG. 1 illustrating the relation of the knife assembly and the scrap deflector; and FIG. 9 is a wiringdiagram.

Referring to FIG. 1, the paper cutter assembly of the invention, generally designated as 1, is shown in operative relation to a xerographic unit, generally designated as 2, which includes a xerographic plate in the form of drum '10 mounted in suitable bearings in the frame of the machine and is rotative at constant rate by motor 11. The 'drum comprises a photoconductive surface 12 on a conductive backing that is sensitized prior to exposure by means of a screened corona charging device 13, which may be of the type disclosed inWalkup Patent 2,777,957, that is energized from a suitable high potential source.

, Exposure of the drum to the light image discharges the 'photoconductive layer in the areas struck by light, whereby there remains on the drum an electrostatic latent image corresponding to the light image projected. To project an a "opaque originalonto surface 12, projection apparatus 3 is employed which may be of a type disclosed in above-cited copending application entitled Xerographic Reproducing Apparatus. An original to be reproduced is manually fed from support tray 14 onto endless belts, 15 which are continually moved at constant rate proportional to the rate of movingweb 40 by drive motor 16. As an original moves on the belts, it passes under glass 17 whereat an optical path is established'from which the image on the original is reflected from mirror 22, thence through an objective lens 23' to mirror 24 through variable width exposure slit25 so as to be exposed normal to a first axial portion of surface 12. Lamp 26 serves to illuminate the original under glass 17 and also serves to emit light to copy detection device 51 in the absence of originals to be reproduced as described below.

For controlling exposure, the aperture width of exposure slit 25 (see also FIG. 3) can be varied by dial 93 having a pointer 94 which indicates the width opening from scale '86 inscribed on the side wall of support 84. Dial 93 is secured to shaft 95 which is rotatably supported in bearing. means 96. Alsosecured to 95 is pinion 97 meshing with gear 98 secured to rotatable shaft 99 which is an extension of support bar 143 and to which leaf 144 is secured. Gear 98 meshes with gear 145 secured to rotatable shaft 146 which is an extension of support bar 147 4 and to which leaf 148 is secured. Rotation of dial 93 thereby varies the aperture width of slit 25.

After exposure the image is developed by developing apparatus 27, which may be of the type disclosed in copending application S.N. 393,058, filed November 19, 1953, in the names of Mayo et al., now abandoned, in which a two-component developer material 28, which may be of a type disclosed in Walkup Patent 2,638,416, is cascaded over the drum surface. The developer material is stored at the bottom of housing 29 wherefrom conveyor 30, driven by motor 31, scoops the material and releases it over chute 37 permitting it to slide down and cascade over electrostatic latent image 76 '(see FIG. 4) forming thereon a powder image 89. As toner component of material 28 is consumed, it is replenished from dispenser bottle 38 at a rate controlled by variable adjustment 39. After developing, the powder image is electrostatically transferred to a paper web support surface 40 by means of a second corona generating device 42 similar to corona generating device 13 mentioned above.

The support surface is obtained from supply spool 41 and is fed over suitable'guide and tensioning rolls and directed into surface contact with the drum in the immediate vicinity of generating device 42. Afteretransfer, the supported surface is separated from the drum surface and guided through a suitable heat fuser 43, which may be of a type disclosed in Crumrine et a1. Patent 2,852,651

tern 75 on surface 12 therefrom, copy detection device51 (see FIGS. 2, 3, 4 and 5 has a member 53 with a triangular slit 52 arranged between adjacent belts 15' and below glass 17 with the top surface of '53 substantially horizontal. In the absence of original copy transporting on belts 15, light emitted from lamp 26 forms an illumination path to photocell 59 by reflecting light from inclined mirror surface 54 down through slot 56 of enclosure 58. Light thereby transmitted is realized by light-sensitive photocell 59 housed in enclosure 60, which is characterized by emitting a variable electrical signal on the realization of light wherein the magnitude of the signal varies .in accordance with the intensity of illumination realized.

In the preferred arrangement, the signal emitted decreases in order of magnitude when there is an obstruction of the illumination path, and increases in order of mag- .nitude when sno obstruction exists. As original copy moves on belts 15 at least a portion thereof effects a temporary obstruction of the illumination path causing cell 59 to emit discrete changes in signal output at the incipience of obstruction and unobstruction.

Electrostatic latent image control patterns 75 are formed on a second axial. portion of surface 12. To produce the pattern, marker assembly 67 is operated by the detection device 51. The marker assembly includes lamps :68, 69 and 70, each enclosed in housings 64, 65 and 66,

respectively, secured to support bracket 71 in. turn slidably secured on a rail portion 72 of marker support frame 73. Each of the lamps are in spaced relation to surface 12 and-are staggered along the axial length of the drum so that each emits a narrow light beam through apertures of their respective housing wherein the beam emitted by ,lamp 70 is on a peripheral path of surface 12 substantially between the beams of 68 and 69 (see FIG. 5).

Lamps 68 and 69 are continuously illuminated, whereas energized by other circuit means in the absence of originals'tobe reproduced, as described below. When all of l the lamps-aresirnultaneously illuminated they effect a dissipation of electrostatic charge in a peripheral band on the-second axial drum portion. However, with lamp 70 extinguished, a narrow band on surface 12 normally dissipated by the illumination effect of lamp 70 retains its electrostatic charge and subsequently is developed by apparatus 27 are hereinbefore described (see FIG. 4). By alternate operation of lamp 70 at variable frequency of operation and duration dependent upon the obstruction period effected by the moving copy, an electrostatic latent image control pattern 75 is formed on surface 12 in spaced relation to electrostatic latent image 76 corresponding in spaced relation to reference points on the original having caused obstruction and unobstruction of the illumination path.

As may be more readily seen in FIG. 4, where the obstruction andunobstruction of the illumination path has been causedby the leading and trailing edges, respectively, of copy to be reproduced, the electrostatic latent image control pattern 75 thus formed bears a spaced relation to the edge of electrostatic latent image 76. It may also be seen that, in the preferred manner of the invention, the successive peripheral line charges which constitute control pattern 75 occur in the direction of drum rotation between successive electrostatic latent images commencing with the trailing edge of one image and terminating with the leading edge of the succeeding image. -To effect lateral positioning of' the control pattern in relation to the edge of drum (see FIG. 3), control knob 79 is secured to the end of rotatable lead screw 81 and has a pointer 80 integral thereof by which the rela- ,tive lateral position of marker assembly 67 is indicated from scale 87. Lead screw 81 is supported in suitable bearing means 82 and 83' of stationary supports 84 and 85, respectively, whereby lead screw- 81 engages bracket 71', suchthat on rotation of knob' 79 it effects lateral movement of bracket 71 and the lamps secured thereto.

In addition to forming a first electrostatic latent image control pattern in spaced relation to an electrostatic latent image of copy to be reproduced, it is desirable, in the absence of copy to be'reproduced, to effect a second electrostatic latent image control pattern since the portion of web which will contact that portion of the drum will in its entirely constitute scrap. The second control pattern so established forms a signal to which a cutter responsively operative therefrom cuts the scrap into prescribed lengths.- The components for effecting this second control pattern are more particularly described in the operational sequence to follow herein, but,'i'n general, is accomplished by electric circuit means which illuminate lamps 70 in the absence of original copy, at predetermined frequency of operation and for a predetermined period of operation. a Another situation frequently occurs wherein two successive originals are too closely spaced, i.e., the leading edge of a following original is within a prescribed minirnum distance of the trailing edge of the leading original and tolwhich the cutter must effect proper response. In this instance if obstruction of the illumination pat-h were relied on, the control pattern effected would be too short in length for subsequent detection and for that' reason electric circuit means, as are more described in theoperational sequence below, precludes less than a" minimum extinguishment period of lamp '70 so as to resultin pattern mark 90 on web 40 of at least /2-inch in length.

By the marker apparatusthus described --electrostatic latent image control patterns are formedon a xerographic plate which subsequently are developed and "transferred to a support surface and translated therefrom as a signal to effectsubsequentcutter operation. Whereas the sig nal produced is described herein withparticular reference to effect operation of a" cutter apparatus; it is apparent that the marker apparatus could be employed to effect marking-signals for other purposes, as, for example, 'to fold, punch, or other related operations in reference to a point on the web, or xerographic reproduction. Furthermore, although particular emphasis is placed on effecting control patterns in spaced relation to the leading and trailing edges of xerographic reproductions, variations in apparatus arrangement would permit effecting control patterns in any relation thereto.

For cutting the web, the cutter is supported on frame 101 (see FIGS. 6, 7 and 8) having side supports 102 and 103 and bottom support 104. Web 40 is continuous ly drawn from supply roll 41 and advanced through the paper cutter by the motive force furnished from motor 105. The force therefrom is transmitted through speed reducer 106 to shaft 107 secured thereto thence to pulley 108 secured thereon. Nonslip belt 109 transmits the motion therefrom to pulley 111, secured to shaft 113, which is rotatably secured to bearing means 114 of side bracket 115 supported from side wall 102. Also secured to shaft 113 is gear 121 which meshes with gear 122 secured to rotatable shaft 123 supported in suitable bearing means of side walls 102 and 103. This effects driving of pulley 124, also secured to shaft 123, and wherefrom belt 125 transmits the driving force to pulley 126 secured to rotatable shaft 127 supported in suitable bearing means 128 and 129 and to which is secured platen rollers 130. The web passes over idler roller and then between rollers'137' and 138, of which roller 137 being secured on shaft 123 is rotative therewith. This frictionallly drives roller 138 secured on rotatable shaft 139 and supported at opposite ends in bearing means 140 of pivot supports 141 (one shown) which are pivotally secured to side supports 102 and 103by pins 142. Roller 138 is urged to frictionally engage against roller 137' by the resilient spring action of springs 149 (one shown) secured between 104 and 141. For threading purposes, 138 can be spaced away from 137 by the action of cams 150 (one shown) when rotating handle 151 is securedto shaft 152 so that the rearward end of each 141 depresses against springs 149, lowering roller 138. Therefrom web 40 when passing between horizontal guides 153 and 154 is moved by platen roller 130 thereagainst. The pressure of 130 applied on web 40 is adjustable by rotation of handle 155 secured to shaft 156 such that pinion 157 also secured thereon and engaging rack 158 effects a raising or lowering of shaft 127.

As the web passes below detector means 167 the area thereof on which pattern marks 90 appear is illuminated by side lights 168 and169. At the incipient detection of a leading edge of mark 90 passing into view under opening 170 of housing 178 it is reflected frommirror 171 through lens 172 held by retainer ring 179- into tube 173 to photocell 174 which immediately emits a discrete change in electrical signal through electric circuit means shown in FIG. 9 which constitutes a trailing edge signal. At the incipient detection of the mark passing out from under opening 170, another discrete change in electrical signal is emitted by 174 constituting a leading edge signal. Detector means 167 is supported in relation to the web 40 in block 176 supported by shaft in turn secured at opposite'end in stationary'bracket 177.-

As the web emerges from between guides 153 and 154 .it moves between knife member 184 in ineffective position and bed plate 185 of the knife assembly generally designated'as 183 (see FIG; 8). The table plate 191 is secured by bolts to shock support plate 188 secured to support walls 102 and 103 of support frame 101. Secured between table plate 191 andthe shock support plate are resilient shock mounts 192* which absorb vibration induced by cutter operation. Solenoids 197 and 198are eachmounted on table plate 191 with their plunger elements secured to journal supports 201 and 202; respectively. Shaft 203 secured in and between journals 201 and 202 isrotatably extended through bearings 207 of yoke 204. At the forward end of 204, as viewed on FIG. 8, rotatable pin 209 supports bracket 208 which in turn supports knife member 184. Rear support braek et 210 has a rotatable pin 215 extending through it to maintain the rear of 204 substantially horizontal as sole-' noids 197 and 198 are actuated to descent knife 184. Bolt 216, extending vertically through 204, on its descent opens microswitch normally-closed contacts 1LS-1 and 1LS-2. As knife member 184 descends, its rearmost edge is maintained slidably in contact against bed plate 185 by rollers 217 and 218 each rotatably secured to a pivot arm 219, in turn pivotally secured by pins 220 to side brackets 221 supported from the bed plate. Bolt 222, secured between leaf spring 223 and 219 urges the rollers firmly against the knife. For dampening the end of the descendingstroke, cylinder 206 includes a rubber plug (not shown) which is compressed at the end of stroke by a piston 211 and adjustment knob 205 permits variable-setting of the stroke.

' After the knife has descended to cut the web, the circuit of solenoids 197 and 198 are de-energized as is described in the operational sequence below, and springs 224 and 225 secured at their upper end to respective brackets 226 and 227 and at their lower end to the knife immediately hoist the knife restoring it to ineffective position established by stop blocks 234 and 235.

After cutting the web, it is desired to separate the reproduction from scrap. For effecting the separation, scrap deflector assembly generally designated as 238 is secured to the knife assembly by means of bifurcated support brackets 239 and 240 such that xerographic reproductions are sorted into document bin 241 and scrap paper accumulates in scrap bin 242. Platen roller 247 is secured to shaft 248 which is rotatably supported in suitable bearing means of supports 239 and 240 and is rotated at constant rate by pulley 249 secured thereto and driven by belt 250 driven by pulley 251 secured on shaft 127 (FIG. 6). Wheel rollers 252are secured on shaft 253 which is rotatably supported in bearing means of supports 239 and 240 wherein rollers 252 are rotated by the frictional action thereagainst of platen roller 247.

Deflector 259 is mounted so as to be pivoted on shaft 248 and is secured at its lower end by pin 258 to lateral arm 260 in turn secured to plunger 261 of solenoid 262. Energizing of the solenoid 262 moves arm 260 so as to partially rotatedefiector 259 in a manner obstructing entrance of web cuttings-between rollers 247 and 252 as to deflect them to scrap bin 242. With solenoid 262 deenergized, spring 263 retracts arm 260 and the deflector as to render the deflector in a horizontal plane to guide reproductions thereover into and between rollers 247 and 252 emerging into document bin 241. v In operation, all the components of xerographic unit 2 are operative. Corona generating device 13 is continually applying a uniform electrostatic charge on surface 12 and in the absence of copy a first axial portion thereof is substantially dissipated by the exposure of continuous light from lamp 26 being reflected from mirror 22 to lens 23, mirror 24 and through aperture 25. Developing apparatus 27 is continually cascading powder 28 over surface 12 and web 40 is continuously moved between corona generating device 42 and surface 12 through fuser 43 and through cutter assembly 1 as aforesaid. Lamps 68 and 69are'illuminated and photocell 59 realizes an intense illumination from lamp 26.

Referring to FIG. 9, positive rectified direct current is obtained fromthe part of the circuit generally outlined as 267 and negative rectified direct current is obtained from the part of the circuit generally designated as 268; Switches S-l, S2, S-3 and S4 are selectively set to coincide at any of five optional positions whereby the first position is o and the cutter apparatus 1 is de-energized. In the remaining switch positions, the cutter apparatus responds to effect operation as (1) cut on leading and trailing edges of copy and operate scrap deflect, (2) cut on leading edge only, (3) cut on trailing edge only, and (4) cut on leading and trailing edge only. For discussion purposes, it is assumed that all of the switches have been set to effect cutting on the leading and trailing edge of xerographic reproductions and also operate the scrap deflector assembly 238. Referring therefore to all figures, copy to be reproduced is first fed from support tray 14- onto moving belts 15. As the copy is moved thereon the leading edge of copy encroaches on slit 52 such that when the leading edge effects an obstruction of the illumination path between lamp 26 and detection device 51, photocell 59 realizing the decrease in illumination, effects a discrete change in electrical signal activating pentode V-5 to a bias below cut-off so as to de-energize relay 1CR. This has the effect. of de-energizing relay 8CR from contact 1CR-1 and permitting normally closed contact 8CR to close energizinglamp 70. After exposure of the original .at the instant the trailing edge of the copy has passed over slit 52 so as to re-admit light from lamp 26 to cell 59, the discrete change of signal emitted by photocell 59 activates the grid of pentode V-5 above cut-off, energizing relay 10R and energizing relay 8CR therefrom so as to effect opening of normally closed contact 8CR and extinguishing lamp 70. While lamp is extinguished a peripheral path on a second axial portion of surface 12 between the illumination of lamps 68 and 69 retains its electrostatic charge. As succeeding originals are fed into belts 15 at a rate between each original in excess of a prescribed minimum time, each leading edge in obstructing the-illumination path from lamp 26 to photocell 59 again effects energizing of lamp 70 so as to commence dissipating the path of electrical charge affected by its illumination. The alternating operation of lamp 70 effects an electrostatic latent image control pattern commencing and terminating in spaced relation on surface 12 to the trailing and leading edge respectively of successive electrostatic latent images 76. These latent images and latent image control patterns are then xerographically developed, transferred and fixed in the same spaced relation onto support web 40 as aforesaid.

Since mark 90, which constitutes control pattern, is intended as a signal from which a subsequent operation is dependent, the mark must be of sufficient length for its detection. When successive originals are closely spaced such that less than a minimum mark would be otherwise effected between the trailing edge of the leader print and the leading edge of the follower print, relay 8CR which has been selected having a characteristic release time of approximately /a second delays energizing of lamp 70 for /a second. On a web moving at the rate of 4 inches per second this produces a minimum pattern mark thereon of /2 inch in length.

In the event there is a prolonged absence of originals supplied to the xerographic apparatus for reproduction while it is operative, the web consumed constitutes scrap and it is desirable to effect a pattern mark from which a cutter in response thereto cuts the web into prescribed scrap lengths. With each energizing of relay ICR (absence of original) relay 7CR is energized in addition to relay 8CR. However, relay 7CR is characterized by an operating delay of approximately 2 secondsso as to permit effecting a pattern mark of approximately 8- inches be fore the normally open contacts 7CR-2 energize lamp 70. When relay 7CR becomes operative, capacitor C-11 is dis chargedso as to release 7CR in its characteristic release time of approximately second, thereby energizing lamp 70 for /8 second and effecting /2 inch interruption of pat tern mark. With a continued absence of originals, this cycle is repeated effecting 8 inch bordermarks and /2 inch interruptions. In the event copy to be reproduced are fed to the apparatus in the interim, the illumination path ob struction effects de-energizing relaylCR and consequently relay 7CR. After emerging from the xerographic appa ratus 2, web 40, bearing xerographically reproduced image 91 and control pattern mark 90, moves into paper cutter assembly 1. The surface area on web 40 occupied bythe xerographic control pattern mark 90 is continually illu-' minated by lamps 168 and 169,and at the incipience of a pattern mark detection or detection of its termination sensed by detector means 167, a discrete change in elec trical signal is emitted by photocell 174. On incipient de tection of a border mark, or a decrease in illumination at photocell 74,. the discrete change of signal emitted decreases in order of magnitude and corresponds to a trailing edge signal whereas on incipient detection of border mark. termination, or increase in illumination at photocell 174, the discrete change of signal emitted increases in order of magnitude and corresponds to a leading edge signal.

On detection of a leading edge signal, the signal of 174 is transmitted through amplifier circuit 269 and differentiatingcircuit 270 and through triode V7B to energize relay 3CR through normally closed contacts of 1LS-2 and 4CR-2 thereby closing contacts 3CR-1 and 3CR-2. Contact. 3CR-1 closes to form a holding circuit through triodeV-SB whereas 3CR-2 energizes timing clutch 273 of timer 274 to start the timing cycle. When timer 274, having a preset time delay, energizes contacts 1TR-2 and lTR-3, relay 4CR and solenoids 197 and 198 are simultaneously operated thereby opening contact 4CR-2 and descending knife 184 to cut web 40 in spaced relation to a leading edge of. a xerographic reproduction. As the cutter completes its downward strike, bolt 216 strikes microswitch 1LS-1 and lLS-2 opening their normally closed contacts. Since 4CR and the solenoids are energized by timer 274, the contacts of 4CR-2 are open as the knife completes its downward stroke and the holding circuit of relay 30R is opened by opening 1LS-2 to deenergize clutch 273, restoring timer 274 to its original position, and de-energizing the solenoids and releasing relay 4CR. As solenoids 197 and 198 are de-energized, springs 224 and 225 instantly hoist the knife to ineffective positions On detection of a trailingedge signal, a pulse applied to the grid of triode .V-7A from photocell 174, is transmitted through amplifier circuit 269 and differentiating circuit 271 to effect energizing of relay 2CR through normally closed contacts of 1LS1 and 5CR2. Contact 2CR1 of relay 2CR is closed to form a holding circuit through triode VSA, whereas contact 2CR-2 energizes clutch 278 of timer 279 having a preset time delay to start the timing cycle. When timer contacts 2TR2 and 2TR3 are energized they operate relay 5CR and solenoids 197 and 198 of'the cutter descending the knife to cut web 40 in spaced relation to a trailing edge of a xerographic reproduction. As the cutter completes its downward stroke, bolt 216 strikes microswitch 1LS-1 and 1LS-2opening their normally closed contacts. Since SCR and the solenoids are energized by timer 279, the normally closed contacts 5CR2 are open as the knife completes its downward'stroke and the holding circuit of relay 2CR is opened by 1LS-1 to effect release. Opening then of 2CR-2 de-energizes clutch 278 restoring timer 279 to its original position and de-energizing relay SCR and the solenoids. As solenoids 197 and 198 are de-energized, the knife is restored to ineffective position as before. of relay 5CR on the trailing edge signal energizes relay 6CR from contact SCR-l closing contact 6CR-1 to hold the circuit closed while 6CR-2 is closed to energize solenoid 262 and effect scrap deflector operation. Solenoid 262 remains so energized until a leading edge signal is received energizing relay 4CR so as to open contact 4CR-1.

If, however, as stated previously, two successive originals have followed closely so as to'elfect a minimum /2- inch border mark between separate reproductions, it is desired to effect a single cut to separate the two reproductions whereby the cut is characterized by a leading edge signal to result in both reproductions being disposed into document bin 241. After triode V8A has formed a holding circuit with relay 20R on a trailing edge signal, and a leading edge signal is received by triode V7B within a maximum prescribed time after V-7A has received the trailing signal, the signal of V7B has the To operate scrap deflector 259, energizing effect of lowering the grid. bias of V 8A below cut-off opening the holding circuit of 2CR and eliminating the trailing edge signal. If, however, the signal to V7B has been received beyond the maximum prescribed time after receipt of signal by V-7A, the voltage across capacitor C-15 will have amassed capacity whereby the signal of V7B imparted to triode V-SA is insufficient to lower the grid bias of V-8A below cut off.

An analogous situation occurs wherein a /2-inch interruption in pattern mark is detected in the case of extended scrap length. However, in this situation, the first signal received is equivalent to a leading edge signal and the second signal is equivalent to a trailing edge signal. Again, as before, when successive signals are received within a prescribed maximum time, it is desired to give effect to the second signal and negate or eliminate the first thereby to effect a cut in this instance characterized by a trailing edge signal so as to operate the scrap deflector 259 in conjunction therewith and direct scrap into bin 242. After triode V8B has formed a holding circuit with relay SCR on a leading edge signal and then a trailing edge signal is received by triode V-7A within a maximum prescribed time after V7B has received its signal, the signal received by V-7A has the effect of lowering the grid bias of V8B below cut off opening the holding circuit of 3CR and eliminating the leading edge signal. However, where the signal to V-7A has been received beyond the maximum prescribed time after receipt of signal by V-7B, the voltage across capacitor C-17 will have amassed capacity whereby the signal of V-7A imparted to triode V8B is insufficient to lower the grid bias of V8B below cutoff.

In the preferred arrangement of the apparatus with detector means 167 located approximately two inches from knife member 184, it is readily conceivable that a trailing edge control pattern and leading edge control pattern following in relatively close succession will pro- 'duce two cut signals before the cutter operates. Contacts 4CR-2 and 5CR-2 are operatively opened only on a leading or trailing edge out respectively to assure that each of the signals effect their separate cut.

By the apparatus thus described thereis disclosed apparatus for marking and cutting a web type surface on which xerographic reproductions are formed. There is also disclosed apparatus for forming electrostatic latent image control patterns on a xerographic drum in spaced relation to an electrostatic latent image of copy to be reproduced and apparatus to cut a continuous web in spaced relation to the leading and trailing edges of a xerographic reproduction printed thereon at variable spacing. Additional means are disclosed for effecting separation of xerographic reproductions from scrap.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a xerographic reproducing apparatus a marking device for effecting an electrostatic latent image control pattern on a xerographic plate in spaced relation to an electrostatic latent image of copy to be reproduced wherein the xerographic apparatus includes a xerographic plate moving at constant rate, charging means for applying a uniform electrostatic charge on the plate surface, means to move copy at constant rate past an exposure means to expose the copy to a first portion of the plate surface forming an electrostatic latent image thereon; said marking device comprising in combination a light-tight enclosure having an opening therein whereby light can enter,

a first light source arranged to project light into said opening and which is obstructed by at least a portion of copy'moving between the first light source and the opening,

a light-sensitive device within said enclosure which '.emits discrete changes of electrical signal at the incipience of obstruction and unobstruction of said light,

a second light source arranged to illuminate a second portion of the plate surface,

electric circuit means distinguishably responsive to the order of said discrete signal changes thereby to alternately illuminate and extinguish said second light source.

2. In a xerographic reproducing apparatus a marking device for effecting an electrostatic latent image control pattern on a xerographic plate in spaced relation to the leadingand trailing edges of an electrostatic latent image of copy to be reproduced wherein the xerographic apparatus includes a xerographic plate moving at constant rate, charging means for applying a uniform electrostatic charge on the plate surface, means to move copy at constant rate past an exposure means to expose the copy to a'first portion of the plate surface forming an electrostatic latent image thereon; said marking device comprising in combination a light-tight enclosure having an opening therein whereby light can enter,

a first light source arranged to project light into said opening and which is obstructed and unobstructed by the leading and trailing edge respectively of copy moving between the first light source and the opening, 7 l

a photocell within said enclosure which emits discrete changes of electrical signal at the incipience of obstruction and unobstruction of said light,

a second light source arranged to illuminate a second portion of the plate surface,

electric circuit means distinguishably responsive to the Order of said discrete signal changes thereby to alternately illuminate and extinguish said second light source.

3. An apparatus for producing a control pattern on a moving photoconductive surface consisting of means to provide a uniform electrostatic charge on the photoconductive surface,

two continually illuminated laterally spaced light sources positioned, adjacent to the photoconductive surface to define a control pattern area by discharging the electrostatic charge on the photoconductive surface in an area immediately adjacent the desired control pattern area,

an intermediate light source positioned between said two light sources and impinging the photoconductive surface in the control pattern area,

and electrical circuit connected to said intermediate light source to produce intermittent illumination of the control pattern area in response to the occurrence of one or more predetermined events,

a movable member supporting said two light sources and said intermediate light source,

and means to position said support member relative to said photoconductive surface to regulate the location of the control pattern area produced by said two light sources.

4. An apparatus for producing a control pattern on a moving photoconductive surface consisting of means to produce a uniform electrostatic charge on the photoconductive surface,

two continually illuminated laterally spaced light sources positioned adjacent to the photoconductive surface to define a control pattern area by discharging the electrostatic charge on the photoconductive surface in an area immediately adjacent the desired control pattern area, 1 one or more intermediate light sources positioned between said two light sources and impinging on the photoconductive surface in the control pattern area, an electrical circuit connected to said intermediate light sources to produce intermittent illumination in the control pattern area in response to the occurrence of one or more predetermined events thereby discharging the electrostatic charge in select portions of the control pattern area, and means to' position said light sources relative to said photoconductive surface to control the location of the control pattern.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A XEROGRAPHIC REPRODUCING APPARATUS A MARKING DEVICE FOR EFECTING AN ELECTROSTATIC LATENT IMAGE CONTROL PATTERN ON A XEROGRAPHIC PLATE IN SPACED RELATION TO AN ELECTROSTATIC LATENT IMAGE OF COPY TO BE REPRODUCED WHEREIN THE XEROGRAPHIC APPARATUS INCLUDES A XEROGRAPHIC PLATE MOVING AT CONSTANT RTE, CHARGING MEANS FOR APPLYING A UNIFORM ELECTROSTATIC CHARGE ONTHE PLATE SURFACE, MEANS TO MOVE COPY AT CONSTANT RATE PAST AN EXPOSURE MEANS TO EXPOSE THE COPY TO A FIRST PORTIN OF THE PLATE SURFACE FORMING AN ELECTROSTATIC LATENT IMAGE THEREON; SAID MARKING DEVICE COMPRISING IN COMBINATION A LIGHT-TIGHT ENCLOSURE HAVING AN OPENING THEREIN WHEREBY LIGHT CAN ENTER, A FIRST LIGHT SOURCE ARRANGED TO PROJECT LIGHT INTO SAID OPENIG AND WHICH IS OBSTRUCTED BY AT LEAST A PORTION OF COPY MOVING BETWEEN THE FIRST LIGHT SOURCE AND THE OPENING, 